|any naturally occurring carbon or hydrocarbon fuel, such as coal, petroleum, peat, and natural gas, formed by the decomposition of prehistoric organisms|
A hydrocarbon deposit, such as petroleum, coal, or natural gas, derived from the accumulated remains of ancient plants and animals and used as fuel. carbon dioxide and other greenhouse gases generated by burning fossil fuels are considered to be one of the principal causes of global warming.
Coal, petroleum, and natural gas.
Note: All of these fuels were formed from the remains of plants and animals that lived millions of years ago.
Note: All fossil fuels produce carbon dioxide when burned. (See greenhouse effect.)
Note: Burning fossil fuels is a main cause of air pollution.